Building air ventilation systems typically include one or more air filters. These filters are generally positioned to filter air which is drawn from the interior of the building through an air handling system (which may heat and/or cool the air) before the air is discharged back into the building.
For example, in the case of a home, a standard air heating and cooling system typically includes one or more air intakes which are located in the interior of the home. An air filter is often located at each intake for filtering the air as it is drawn into the system. These air filters must be regularly changed so that they are effective in removing particulates from the air and so that the filter does not become clogged and impair the air flow through the system.
Unfortunately, the replacement of a used air filter with a new one is often very difficult. For example, home air heating and cooling systems frequently utilize air intakes which are located in the ceiling. The intake includes a housing or plenum which leads to the air handling devices (fans, heating and/or cooling coils, etc.). An air filter is mounted at the entrance to the intake, such as between a flange thereof and a covering grill or grate. The grate is typically pivotally mounted to the intake housing, such as with hinges. The grate can be maintained in its closed position by one or more latches.
Various difficulties arise when replacing the air filter of such a mechanism. First, the user must generally stand on a ladder in order to reach and unlatch the covering grate due to the in-ceiling location of the intake. This requires a user to balance himself on the ladder while attempting to unlatch the latches, which may involve the use of one or more tools.
In addition, once the grate is unlatched, it must swing down from the ceiling to its open position. Because the user must generally position himself under the grate in order to unlatch it, this swinging motion may either result in the grate hitting the user or the user being forced to change positions on the ladder to allow the grate to swing by them. Either of these actions may result in the user falling from the ladder.
Once the grate is open, the filter is unsecured and will then fall from the intake under the force of gravity. This may cause a dirty filter to hit the user, the ladder, the floor or other items, causing the air filter to shed dust and make a significant mess. As a result, the user must generally stay on the ladder and, while avoiding the swinging grate, grasp the used filter.
The user then must climb down the ladder and obtain a new filter. The user then reverses the process, placing the new filter into the intake and attempting to swing the grate back into place and latch it to hold the new filter.
Some attempts have been made to address these issues, but they also suffer from various problems. For example, U.S. Pat. No. 8,075,031 describes a filter changing system where a user attempts to use a pole with filter grabbing teeth in order to remove a used filter. This mechanism, however, does not address the significant problem with the interplay between the grate and the filter. The system of the '031 patent requires that the user turn on their air system while opening the grate or else the used filter will fall. First, a user may not remember to turn on their air system when replacing the system. Second, in some cases this arrangement may not work. For example, some ceiling vents utilize two side-by-side filters. Once a user removes one of these filters there will be insufficient suction to maintain the other filter in place and it will fall on the user. In addition, this system requires that the user attempt to align a large filter element which as close tolerances to the intake housing, remotely via a pole in order to get a new filter placed into the intake housing.
In addition, some commercial ventilation systems have filter housing which are movable. These systems are generally very large and complex and typically utilize motors or other automated controls to move the housings.